The present invention relates to a lining brick for use in forming refractory linings for receptacles such as furnaces, and particularly for rotary kilns. More specifically, the present invention relates to such a lining brick of the type having a hot side surface adapted to be directed toward the interior of the furnace, a planar shell side surface opposite the hot side surface and adapted to contact the shell of the furnace, first and second pairs of spaced opposite lateral side surfaces extending between the hot side and shell side surfaces, and recesses opening onto the shell side surface.
A lining brick of this general type is disclosed in U.S. Pat. No. 2,230,142. Insulating material is placed in the recesses of these bricks for the purpose of reducing the heat transferred from the interior of the furnace to the furnace shell. To obtain a maximum insulating effect, the recesses on the shell side surface include a center recess between two lateral recesses. Thus, the brick abuts the shell at two narrow webs only. However, it has been determined that during operation of a furnace lined with this type of bricks, due to the relative movement between the lining and the shell, the ceramic brick material of the narrow webs of the bricks crumbles away, thus abrading the brick material. This considerably weakens the strength of the lining. This damage is very serious in a rotary kiln lining, wherein the bricks are subjected to stresses caused by changing loads.
West German DE-OS No. 25 34 973 discloses a lining brick having on the shell side surface one or more recesses that are filled with insulating material. The webs remaining in the vicinity of the insulating material are narrow compared to the size of the recess. Thus, in the area of the webs the brick is weakened considerably so that damage to the bricks occurs during operation.
West German DE-GM No. 76 11 927 discloses a lining brick having holes. The shell side surface of the brick has no openings or recesses and abuts the furnace shell over the entire surface. The total volume of the holes is to be 10 to 30% of the volume of the brick formed without openings. Thus, compared to a full brick without openings, the weight is reduced. This weight reduction has a favorable effect on the cost of the brick. However, it is difficult to form the openings, and it is unlikely that the price of this brick can be lowered to an extent to be commercially feasible. Furthermore, this brick has thin wall sections between adjacent openings, and although these thin wall sections are less apt to be damaged during operation than the webs of the other above discussed prior art arrangements, breakage of such thin wall sections during operation cannot be totally avoided.